Steel girders are used for building bridges,flyovers which are used as road over bridges, for passing railway over canals, valleys etc. The company entered this segment in the year 2005 having got approval from RDSO for manufacturing of welded and riveted type girder. Depending upon the load conditions and spans there are various type of girders.
Steel Box Girder
Steel box girders are used for long spans, where the self weight of the bridge needs to be minimized, and for situations where its excellent high torsional stiffness is of particular benefit. The clean lines of box girders bridges, usually with no visible external stiffening, is generally considered to give a excellent appearance and durability, since there are no traps for dirt and moisture. Steel box Girders are currently being used by Metro Railways in India.
Advantages
High torsional stiffness and strength, giving greater suitability for horizontally curved bridges.
Improved durability and reduced maintenance of protective coatings (less exposed surface, fewer edges, avoidance of exposed horizontal surfaces, no exposed bracing and stiffeners).
I Girder
I steel girders are made in shape of an I by welding the steel plates together which fulfils the function of a I beam(i.e having a greater bending stress bearing capacity). It is given positive camber at its middle since it has greater loads at its middle than at its end. It is mainly used by Highway Authorities of India as road over bridges for commuting of vehicles over railway lines where the distance between two pillars is more 20 metres. I steel girders are used along with concrete and are known as composite girders.
Open Web Girder
Open web through type, semi through type and under slung type are mainly used by Railways for laying of railway tracks over rivers, canals and valleys. In mountain region they are used by highways for crossings. A open web girder may be welded or riveted(although obsolete) type depending upon the load conditions. Open web girders are designed keeping in mind the truss type structure used for transferring loads.